This invention relates to a new and improved system for controlling a diesel powered refrigeration plant, and has particular utility in the food industry.
Present day diesel powered refrigeration plants employed in food storage facilities include trucks, railroad refrigeration cars, and stationary plants. Various factors determine the temperature range settings of these refrigeration plants, such as the thermal capacity of the plant (including the insulation portion) ambient temperature, heat exchange leaks, particularly from open doors, thermal capacity of the food, the required storage temperature of the food itself, and projected weather conditions. The diesel engine is operated continuously to maintain the temperature within the desired range even if this necessitates that heat be supplied to the plant to compensate for over cooling. This, of course, represents a considerable waste of cooling power. If the diesel engine is turned on and off frequently to reduce power costs, the repeated start ups eventually exact a high toll due to engine mantenance.
If it were possible to supply cooling power alone to the refrigerator plant, without requiring heat input, the cooling power could be utilized more efficiently. Also, if the stored cold of the food could be used as a `cold sink`(or heat sink if warming was required), it would be possible to use the diesel engine only intermittently rather than continuously.